#!/bin/bash
#
# Developed by Greg McNeil 2/22/2019 .... converted by Fred Weinhaus 5/5/2019
#
# ------------------------------------------------------------------------------
# 
# Licensing:
# 
# Copyright © Fred Weinhaus
# 
# My scripts are available free of charge for non-commercial use, ONLY.
# 
# For use of my scripts in commercial (for-profit) environments or 
# non-free applications, please contact me (Fred Weinhaus) for 
# licensing arrangements. My email address is fmw at alink dot net.
# 
# If you: 1) redistribute, 2) incorporate any of these scripts into other 
# free applications or 3) reprogram them in another scripting language, 
# then you must contact me for permission, especially if the result might 
# be used in a commercial or for-profit environment.
# 
# My scripts are also subject, in a subordinate manner, to the ImageMagick 
# license, which can be found at: http://www.imagemagick.org/script/license.php
# 
# ------------------------------------------------------------------------------
# 
####
#
# USAGE: typewriter [-f font] [-p pointsize] [-t txtcolor] [-b bgcolor] textfile outfile
# USAGE: typewriter [-h or -help]
#
# OPTIONS:
#
# -f     font          font or font file; only monospaced fonts work; default=CourierNewB
# -p     pointsize     pointsize for font; integer>0; default=24
# -t     txtcolor      color of text; any valid IM color allowed; default=black
# -b     bgcolor       color of background; any valid IM color allowed; default=white
# 
# textfile is a text file containing the lines of text
###
#
# NAME: TYPEWRITER
# 
# PURPOSE:  Creates a typewriter style scrolling text animation.
# 
# DESCRIPTION: TYPEWRITER creates a typewriter style scrolling text animation.
# 
# ARGUMENTS: 
# 
# -f font ... FONT is the font or font file. Only monospaced fonts will work. The 
# default=CourierNewB
# 
# -p pointsize ... POINTSIZE for font. Values are integers>0. The default=24
# 
# -t txtcolor ... TXTCOLOR is the color of the text. Any valid IM color is allowed. 
# The default=black
# 
# -b bgcolor ... BGCOLOR is the color of the background. Any valid IM color is allowed. 
# The default=white
# 
# CAVEAT: No guarantee that this script will work on all platforms, 
# nor that trapping of inconsistent parameters is complete and 
# foolproof. Use At Your Own Risk. 
# 
######
#

# set default values
font="CourierNewB"		#font
pointsize=24			#pointsise
txtcolor="black"		#text color
bgcolor="white"			#background color

# set directory for temporary files
dir="."    # suggestions are dir="." or dir="/tmp"

# set up functions to report Usage and Usage with Description
PROGNAME=`type $0 | awk '{print $3}'`  # search for executable on path
PROGDIR=`dirname $PROGNAME`            # extract directory of program
PROGNAME=`basename $PROGNAME`          # base name of program
usage1() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^###/g;  /^#/!q;  s/^#//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}
usage2() 
	{
	echo >&2 ""
	echo >&2 "$PROGNAME:" "$@"
	sed >&2 -e '1,/^####/d;  /^######/g;  /^#/!q;  s/^#*//;  s/^ //;  4,$p' "$PROGDIR/$PROGNAME"
	}


# function to report error messages
errMsg()
	{
	echo ""
	echo $1
	echo ""
	usage1
	exit 1
	}


# function to test for minus at start of value of second part of option 1 or 2
checkMinus()
	{
	test=`echo "$1" | grep -c '^-.*$'`   # returns 1 if match; 0 otherwise
    [ $test -eq 1 ] && errMsg "$errorMsg"
	}

# test for correct number of arguments and get values
if [ $# -eq 0 ]
	then
	# help information
   echo ""
   usage2
   exit 0
elif [ $# -gt 10 ]
	then
	errMsg "--- TOO MANY ARGUMENTS WERE PROVIDED ---"
else
	while [ $# -gt 0 ]
		do
			# get parameter values
			case "$1" in
		  -h|-help)    # help information
					   echo ""
					   usage2
					   exit 0
					   ;;
				-f)    # get  fontname
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID FONT SPECIFICATION ---"
					   checkMinus "$1"
					   fontname="$1"
					   ;;
				-p)    # get pointsize
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID POINTSIZE SPECIFICATION ---"
					   checkMinus "$1"
					   pointsize=`expr "$1" : '\([0-9]*\)'`
					   [ "$pointsize" = "" ] && errMsg "--- POINTSIZE=$pointsize MUST BE A NON-NEGATIVE INTEGER ---"
					   pointsizetestA=`echo "$pointsize <= 0" | bc`
					   [ $pointsizetestA -eq 1 ] && errMsg "--- POINTSIZE=$psize MUST BE A POSITIVE INTEGER ---"
					   ;;
				-t)    # get  txtcolor
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID TXTCOLOR SPECIFICATION ---"
					   checkMinus "$1"
					   txtcolor="$1"
					   ;;
				-b)    # get bgcolor
					   shift  # to get the next parameter
					   # test if parameter starts with minus sign 
					   errorMsg="--- INVALID BGCOLOR SPECIFICATION ---"
					   checkMinus "$1"
					   bgcolor="$1"
					   ;;
				 -)    # STDIN and end of arguments
					   break
					   ;;
				-*)    # any other - argument
					   errMsg "--- UNKNOWN OPTION ---"
					   ;;
		     	 *)    # end of arguments
					   break
					   ;;
			esac
			shift   # next option
	done
	#
	# get textfile and outfile
	textfile="$1"
	outfile="$2"
fi

# test that textfile provided
[ "$textfile" = "" ] && errMsg "NO TEXTFILE FILE SPECIFIED"

# test that outfile provided
[ "$outfile" = "" ] && errMsg "NO OUTPUT FILE SPECIFIED"


# get im version
im_version=`convert -list configure | \
	sed '/^LIB_VERSION_NUMBER */!d; s//,/;  s/,/,0/g;  s/,0*\([0-9][0-9]\)/\1/g' | head -n 1`


if [ "$im_version" -ge "07000000" ]; then

	# use subshell processing
	# crop does the horizontal typing
	# affine distort does the vertical scroll
	# u.w is width of text line; v.w/10 is the width of an X character; 
	# [fx:round(u.w/(v.w/10))] computation is number of characters.
	(
	while read line; do
		convert \
			-background "$bgcolor" -fill "$txtcolor" \
			-pointsize $pointsize -font "$font" -kerning 1 \
			label:"\ $line " \
			label:"XXXXXXXXXX" \
			-colors 16 -crop "%[fx:round(u.w/(v.w/10))]x1@" \
			-delete -10--1 \
			-coalesce +repage \
			-set delay "%[fx:t==0||t==(n-1)?75:10]" \
			\( -clone -1,-1,-1,-1 -distort affine "0,%[fx:(t+1)*h/n] 0,0" -set delay 10 \) \
			-loop 0 miff:-
	done < "$textfile"
	) | convert - \
			\( -clone 0--1 -layers merge +repage \) \
			+insert -loop 0 \
			"$outfile"

else
	# use subshell processing
	# crop does the horizontal typing
	# affine distort does the vertical scroll
	# u.w is width of text line; v.w/10 is the width of an X character; 
	# [fx:round(u.w/(v.w/10))] computation is number of characters.
	# duplicate 7 frames at start and end in place of computed delay
	(
	while read line; do

		wd=`convert \
			-pointsize $pointsize -font "$font" \
			label:"\ $line " \
			label:"XXXXXXXXXX" \
			-format "%[fx:round(u.w/(v.w/10))]\n" info: | head -n 1`

		convert \
			-background "$bgcolor" -fill "$txtcolor" \
			-pointsize $pointsize -font "$font" -kerning 1 \
			label:"\ $line " \
			-colors 16 -crop "${wd}x1@" \
			-coalesce +repage \
			\( -clone 0,0,0,0,0,0,0 \) \
			-insert 0 -insert 0 -insert 0 -insert 0 \
			-insert 0 -insert 0 -insert 0 \
			\( -clone -1,-1,-1,-1,-1,-1,-1 \) \
			\( -clone -1,-1,-1,-1 -distort affine "0,%[fx:(t+1)*h/n] 0,0" \) \
			-set delay 10 -loop 0 miff:-
	done < "$textfile"
	) | convert - \
			\( -clone 0--1 -layers merge +repage \) \
			+insert -loop 0 \
			"$outfile"

fi

exit 0










